The invention relates to a method and to an apparatus for folding together an inflatable airbag jacket of an airbag module for motor vehicles.
Airbag modules for vehicle airbags are manufactured in large quantities. One therefore attempts to simplify and speed up the manufacture of the airbag modules, which includes the folding together of the airbag jacket.
The problem (object) of the invention is to create a possibility of manufacturing airbag modules for motor vehicles as rapidly and simply as possible, with it being desirable for this possibility also to be given in particular for side airbag arrangements in which the airbag deploys downwardly in the manner of a curtain along a vehicle side wall in the vehicle in the event of an accident.
This object is satisfied by the features of the method claim 1 and in particular in that the at least partly spread out airbag jacket is arranged in at least one folding pocket and a folding volume of the folding pocket which contains the airbag jacket is reduced in size.
In accordance with the invention the airbag jacket is folded together or gathered by means of the folding pocket in that the folding volume, that is, that region of the folding pocket in which the airbag jacket is arranged, is reduced in size. An essential advantage of the invention consists in that the folded together airbag jacket is still arranged within the folding pocket at the end of the folding process. The folding of the airbag can thus be secured through the folding pocket which surrounds the folded together airbag jacket.
At the same time the folding pocket serves as a cover which protects the folded together airbag jacket. Thus no further measures are required for the securing of the folding and for the protection of the folded airbag jacket. The folding pocket with the folded together airbag jacket which is arranged in it can be mounted in a vehicle as an airbag module or as constituent of the airbag module.
Through the folding method in accordance with the invention consequently the folding together of the airbag jacket and thus the manufacture of airbag modules is considerably simplified and speeded up.
A further advantage of the folding of the airbag jacket in accordance with the invention in a folding pocket consists in that the danger of damage to the airbag jacket is a minimum, since the airbag jacket comes in contact exclusively with the folding pocket and a direct contact with other objects is avoided.
Advantageous is also that the folding volume of the folding pocket can in principle be brought to any size as small as desired. Through reducing the size of the folding volume a minimum packing size of the folded together or gathered airbag jacket can therefore be achieved.
In principle the folding method in accordance with the invention can be used for the manufacture of any desired packing shapes of the folded together airbag jacket. In accordance with a particularly preferred exemplary embodiment of the invention the airbag jacket is folded together to form an elongate packing shape.
Through this the folding method in accordance with the invention can be used in the manufacture of side airbag arrangements, the airbag of which deploys in the manner of a curtain in the event of an accident.
The side airbag arrangements can comprise at least one gas tube which is provided with a gas outlet opening and which extends at least region-wise through the airbag jacket. Through fixing the gas tube the airbag jacket can be fixed region-wise, so that the airbag jacket can be pressed against the fixed gas tube through moving the folding pocket relative to the gas tube. The gas tube thus serves as a support or holding member for the airbag jacket.
This folding possibility is in principle also given in other support or holding members which are provided at airbag modules, which are fixed through suitable means and against which the airbag jacket is pressed by means of the folding pocket through reduction of the folding volume.
In accordance with a further preferred exemplary embodiment of the invention at least one material layer is laid around the airbag jacket for forming the folding pocket.
In this the folding pocket can be formed in a particularly simple way by a single material layer, which is e.g. first spread out and onto which the at least partly spread out airbag jacket is then placed. Through folding over of the region of the material layer which is not covered by the airbag jacket the folding pocket then arises, between the side walls of which the airbag jacket is arranged in a planar manner.
In principle a hanging folding pocket with substantially vertical side walls, between which the airbag jacket is hung, can also be provided in accordance with the invention. Through drawing upwards of at least one side wall of the folding pocket the airbag jacket is then moved in the direction of a fixed region of the airbag jacket and e.g. pressed against a gas tube which fixes the airbag jacket.
In accordance with a further preferred embodiment of the invention the folding volume is reduced in size at least substantially without folding the folding pocket.
Through this it is ensured that the airbag jacket is always surrounded by a substantially fold-free jacket both during the folding together and in the finally folded together state. An interlocking of the folding pocket and the airbag jacket is thus reliably avoided.
In this it is preferred for the volume reduction to take place through moving the folding pocket, in particular through drawing at the folding pocket, in a direction which extends approximately parallel to the plane of spreading out of the airbag jacket. For this, preferably one side wall of the folding pocket is fixed and the folding volume is reduced in size through drawing at another, in particular at the oppositely lying, side wall of the folding pocket.
In accordance with a further preferred exemplary embodiment of the invention the reduction of the folding volume takes place within a folding space, through which the packing size of the airbag jacket is limited during the folding together in directions which deviate from a folding direction, in particular approximately perpendicular to the folding direction.
Through folding together of the airbag jacket within a folding space of this kind it is automatically ensured that a maximum size of the package formed by the folded together airbag jacket, which can be set through the choice of the dimensions of the folding space, is not exceeded. The folding principle in accordance with the invention, in which the airbag jacket is folded together or gathered by means of the folding pocket, is in principle independent of the size of the folding space and requires in particularxe2x80x94apart from the material thickness of the airbag jacket and of the folding pocketxe2x80x94no minimum dimensions of the folding space, so that airbag jacket packages of in principle any desired size can be produced through adjusting the folding space dimensions.
Furthermore, it is preferred for the reduction of the folding volume to take place between two limiting surfaces which extend at least substantially parallel and which are formed in particular at plate-shaped limiting members.
The folding space can e.g. be formed by two plates which extend in parallel, so that the airbag jacket is folded together between the two plates. The reduction of the folding volume of the folding pocket and thus the folding of the airbag jacket takes place in a folding direction which lies in a plane which extends approximately parallel to the plates. Perpendicularly to this folding direction the dimensions of the airbag jacket package which arises during the folding together are limited through the plates to the plate spacing.
In accordance with a further preferred embodiment of the invention the folding pocket is closed after the folding together of the airbag jacket to the final packing size. In particular through connection, preferably welding and/or sewing, of oppositely lying side walls of the folding pocket.
Through this the folding pocket forms a protective envelope which surrounds the folded together airbag jacket and which on the one hand secures the folded package produced in that it prevents an unfolding or relaxation of the airbag jacket, and which on the other hand protects the airbag jacket from external influences. Additional measures for securing the folding or for protecting the airbag jacket respectively can therefore be dispensed with.
The object of the invention is also satisfied through the features of the apparatus claim 13 and in particular in that the apparatus comprises at least one folding pocket for the reception of the at least partly spread out airbag jacket and an actuation device by means of which a folding volume of the folding pocket which contains the airbag jacket can be reduced in size.
The folding pocket is preferably manufactured of a textile and/or fabric material, for example of nylon.
Through this, ideal flexibility and stability properties can be imparted to the folding pocket.
In accordance with a further preferred embodiment of the invention the folding pocket is provided with at least one preferably line-shaped or strip-shaped tear-open region.
The folding pocket can thereby serve as a cover or envelope for the folded together airbag jacket in the state of being mounted in a vehicle, which tears open during the inflation of the airbag at the tear-open region which is provided for this purpose in order to enable the deployment of the airbag jacket.
In accordance with a further preferred exemplary embodiment of the invention a fixing device for the airbag jacket is provided, which is preferably arranged outside a folding space for the folding pocket.
The fixing of the airbag jacket enables the folding pocket to be moved relative to the fixed region of the airbag jacket and the airbag jacket to be folded together or gathered respectively by means of the folding pocket in the direction of the fixed region of the airbag jacket.
In this it is preferred for the fixing device to be formed for the fixing of a support member of the airbag module, to which the airbag jacket is connected.
In this the airbag jacket can be pressed together between the folding pocket and the support member in that the airbag jacket is for example drawn or gathered respectively against the support member through drawing at the folding pocket.
The support member can be the gas tube of an airbag module for a side airbag arrangement, which extends at least region-wise within the airbag jacket.
The gas tube which serves for the inflation of the airbag and which is preferably provided with a plurality of gas outlet openings serves here at the same time as an abutment for the airbag jacket which is pressed together or gathered respectively by means of the folding pocket.
The folding apparatus in accordance with the invention can be designed in such a manner that at the end of the folding process the gas tube is arranged within the folding pocket together with the folded together airbag jacket. Thus at the end of the folding process a module is present which is ready for installation and which can be installed in a vehicle as an airbag module or as a constituent of the airbag module.
In accordance with a further preferred exemplary embodiment of the invention the folding apparatus is subdivided into a plurality of sections, which can preferably be displaced relative to one another. The subdivision into a plurality of sections enables a specific packing shape of the folded together airbag jacket to be intentionally realized which is predetermined through the manner of the arrangement of the sections. Through the preferred displaceablity of the sections, different packing shapes of the folded together airbag jacket can be achieved with one folding apparatus.
In particular for forming differently curved elongate packing shapes the fixing or clamping device respectively which is provided for fixing the airbag jacket or a gas tube of the airbag jacket respectively can be designed to be displaceable.
An airbag module which comprises the folded together airbag jacket and which is a constituent of a side airbag arrangement can thereby be intentionally adapted to the respective use or vehicle type.
Further preferred embodiments of the invention are also set forth in the subordinate claims, the description and the drawings.